Welker reportedly took MDMA that was cut with amphetamines while at the Kentucky Derby and tested positive in May.
The suspension was appealed two weeks ago. Notice that the appeal was denied came today, according to reports. Welker will be eligible to return for the Broncos' Week 6 game against the Jets.
Welker, a five-time Pro Bowler, has recorded at least 70 receptions and 700 receiving yards each of the last seven years.
The 33-year-old had been working his way back after suffering a third concussion in 10 months during a preseason game earlier this month.
The Broncos open the season Sunday against the Indianapolis Colts.
- Chris Johnson